SubDrive/MonoDrive
Description and Features
Description
The Franklin Electric SubDrive/MonoDrive is a variable frequency controller that uses
advanced electronics to protect the motor and enhance the performance of standard
pumps used in residential and light commercial water system applications. When used
with Franklin Electric motors (see Table 2 on Page 19), the SubDrive/MonoDrive provides
constant "city-like" water pressure by eliminating the effects of pressure cycling associated
with conventional water well systems.
Features and Benefits
Constant Water Pressure
The Franklin Electric SubDrive/MonoDrive provides consistent pressure regulation using
advanced electronics to drive a standard motor and pump according to the pressure
demands indicated by a highly accurate, heavy-duty, long-life pressure sensor. By
adjusting the motor/pump speed, the SubDrive/MonoDrive can deliver constant pressure
dependably, even as water demand changes. For example, a small demand on the system,
such as a bathroom faucet, results in the motor/pump running at a relatively low speed. As
greater demands are placed on the system, such as opening additional faucets or using
appliances, the speed increases accordingly to maintain the desired system pressure.
Using the provided pressure sensor, system pressure can be set in the range of 25 – 80 psi
(1.7 – 5.5 bar).
Reduced Tank Size
Conventional systems use larger tanks in order to store water, whereas SubDrive systems
utilize a smaller tank in order to maintain constant pressure. See Table 3 on page 20 for
pressure tank size requirements.
Reduced Pump Size
SubDrive/MonoDrive controllers fit the pump to the application by adjusting the speed of
the pump and motor. In SubDrive applications a pump with a power rating of half the motor
power rating can be used when properly sized. See pump sizing information on page 21.
Over Temperature Foldback
SubDrive/MonoDrive controllers are designed for full power operation in ambient
temperatures up to 122 °F (50 °C) at nominal input voltage. In extreme thermal conditions,
the controller will reduce output power in an attempt to avoid shutdown and potential
damage while still trying to provide water. Full output power is restored when the internal
controller temperature cools to a safe level.
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